Fuel injection nozzle



3 Sheets-Sheet 1 Filed April 11, 1967 FIGZ.

F'IGI.

INVENTOR: FRANK DE LUCA ATTYS.

June 11, 1968 F. DE LUCA 3,387,790

FUEL INJECTION NOZZLE FRANK DE LUCA ATTYS.

June 11, 1968 DE 3,387,790

FUEL INJECTION NOZZLE Filed April 11, 1967 I5 Sheets-Sheet 3 ATTYS.

United States Patent T 3,387,790 FUEL INJECTION NOZZLE Frank De Luca,Thompsonville, Conn., assignor to American Bosch Arma Corporation,Springfield, Mass, a corporation of New York Continuation-impart ofabandoned application Ser. No. 561,489, June 29, 1966. This applicationApr. 11, 1967, Ser. No. 633,666

11 Claims. (Cl. 239-453) ABSTRACT OF THE DISCLOSURE A fuel injectionnozzle assembly comprising a holder, a nozzle mounted at one axial endof the holder having a bore defining a fuel chamber and a valve membermounted for axial movement in the bore of the nozzle. The assemblyfurther includes a plug threadedly mounted in the holder and a stemspaced from the plug to adjust valve lift and spring biasing means inthe holder for normally seating the valve in a closed position. The stemand valve have axially extending bores therein so that fuel from theinlet in the holder passes through to the fuel chamber surrounding thevalve at the lower end of the nozzle. The tail section of the valve hasa pair of angled fuel passageways which connect with the fuel chamberand the axial bore in the tail section of the valve.

This is a continuation-in-part of my prior application Ser. No. 561,489,filed June 29, 1966, for Fuel Injection Nozzle, now abandoned.

The present invention relates to improvements in fuel injection nozzles.

Some of these fuel injection nozzle assemblies conventionally comprisean elongated holder and a nozzle mounted at one end of the holder, theentire assembly being mounted in an elongated bore in the enginecylinder head to supply fuel to the cylinders of the engine.

In these assemblies, one end of the holder is provided with an inletadapted to be connected to a suitable fuel supply source and an axialpassage is provided in the holder which communicates with a fuelpassageway in the nozzle to direct fuel to an annulus in the axial endface of the nozzle confronting the holder. From the annulus, fuel passesthrough two or more fuel ducts in the nozzle to an enlarged annular sumpsurrounding a valve member mounted for axial movement in an axial borein the nozzle. By this arrangement, fuel pressure build up in the sumpraises the valve against the bias of a spring in the holder to permitthe fuel to pass through spray orifices in the outer free end of thenozzle tip.

Several disadvantages or drawbacks are noted in the conventional type offuel injection nozzle assembly discussed above. For example, it has beenfound that it is diflicult to reduce the size of these assemblies interms of cross sectional dimension by reason of the separate axialpassage for the fuel, the axial bore for the valve element and chamberfor the valve actuating spring. Nozzle assemblies of reduced crosssection are desirable to permit more space in the engine cylinder headfor larger valves and thus improve the volumetric efficiency of theengine. Furthermore, since these assemblies are comparatively small insize, the construction thereof is difiicult due to the precisiondrilling required to form these fuel passageways or ducts and otherinternal bores or chambers in the holder and nozzle.

Moreover, the sump tends to trap dirt and foreign particles and isdiflicult to clean thoroughly. Also, the sump, annulus and seat providean excess parasitic or dead fuel volume which makes it difficult tocontrol fuel injection characteristics. Additionally, in enginesemploying Patented June 11, 1968 the sump-type fuel injection nozzlefuel consumption is high and the engine tends to smoke. Further it hasbeen found that various moving parts of the assembly are extremelysensitive and that conventional spring mountings for the valve elementproduce side thrusts on the valve member causing sticking and hanging upof the valve. Furthermore, in the conventional fuel injection nozzleassemblies discussed above, flow of fuel is turbulent which again mayresult in valve sticking and may produce cavitation or erosion.

In accordance with the present invention the fuel passageways or thelike in the various elements of the entire assembly are located axiallyand centrally thereof to permit the entire assembly to be made of a muchsmaller cross section. More specifically, the fuel injection nozzleassembly of the present invention includes a holder and a nozzle tipmounted at one end of the holder. A tubular plug is mounted in the endof the holder remote from the nozzle, the inner end of which is spaced apredetermined distance from the valve assembly in the closed position ofthe valve to define a gap controlling valve lift.

The nozzle comprises the usual body portion and an elongated tip orshank, the body portion having a bore in which the valve element slidesand a lower bore section defining a fuel chamber. The valve assemblyincludes an elongated hollow tubular stem mounted in a socket in thetail section of the valve head which is guided adjacent its upper end inthe axial bore in the holder. A biasing spring mounted in a springchamber in the holder ci cumscribes the stem and serves its normalfunction to bias the valve assembly to a closed position. The head ofthe valve is of a streamlined configuration and is connected to the tailsection by a reduced neck portion. By this arrangement, fuel enters thefuel injection nozzle assembly through the central opening in the plug,fiows through the hollow stem and into the fuel chamber throughdiametrically opposed angled connecting passages in the tail section ofthe valve. The head of the valve serves as a venturi in the fuel chamherso that flow through the fuel chamber is laminar. This assembly iscomprised of comparatively few parts so that it is easy and economicalto make. Furthermore, the valve assembly is guided on either side of theactuating spring to minimize thrust.

With the foregoing in mind, an object of the present invention is toprovide a fuel injection nozzle assembly of substantially smallerdimensions particularly in cross section thereby permitting more spacein the engine cylinder head for larger valves and thus improve thevolumetric efficiency of the engine.

Another object of the present invention is to provide a new and improvedfuel injection nozzle assembly with axial high pressure fuel passagesfor ease of machining and reduction of fuel volume.

Still another object of the present invention is to provide a hollowvalve of relatively short length with reduced inertia which facilitateshigh speed operation.

A still further object of the present invention is to provide a novelfuel injection nozzle assembly wherein the valve is guided at both endsand the actuating spring is positioned between the terminal ends of thevalve so as to make the valve less susceptible to side thrust effectsfrom the actuating spring.

Another object of the present invention is to provide a fuel injectionnozzle assembly including a valve characterized by novel features ofconstruction and arrangement wherein side thrusts are minimized toinsure more reliable functioning of the valve and flow through theassembly is laminar to minimize erosion and cavitation.

A further object of the present invention is to provide a separatefitted assembly of valve and nozzle tip which can be readily serviced orreplaced.

These and other objects of the present invention and the variousfeatures and details of the operation and construction thereof arehereinafter more fully set forth with reference to the accompanyingdrawings, wherein:

FIG. 1 is a side elevational view of a fuel injection nozzle assembly inaccordance with the present invention;

FIG. 2 is an enlarged sectional view through the assembly showing thesame mounted in an opening in an engine cylinder head;

FIG. 3 is an enlarged sectional view similar to FIG. 2 of anotherembodiment of fuel injection nozzle assembly in accordance with thepresent invention;

FIG. 4 is an enlarged fragmentary sectional view of the lower terminalend of the assembly with the valve in a closed position;

FIG. 5 is a fragmentary view similar to FIG. 4 showing the valve in anopen position;

FIG. 6 is a sectional view similar to FIGS. 2 and 3 of still anotherembodiment of fuel injection nozzle assembly in accordance with thepresent invention; and

FIG. 7 is an enlarged sectional view of the lower stem section.

Referring now to the drawings and particularly to FIG. 2 thereof, thefuel injection nozzle assembly includes a nozzle holder 10, a fuelinjection nozzle 12 mounted at the lower axial end of the holder bymeans of a cap nut 14 for axial movement and a valve assembly 15 mountedin the nozzle. The fuel injection nozzle as sembly is adapted to bemounted in an elongated stepped opening 16 in the cylinder head 18 todeliver fuel to the combustion chamber thereof.

The holder 10 is an elongated generally cylindrical member having a fuelinlet 22 at its outer axial end and an axially extending upper boresection 24 which is enlarged adjacent the lower end of the holder as at25 to define a spring chamber C. An externally threaded plug 26 ismounted in the upper bore section 24 of the holder, the plug 26 havingan axially extending central passage 28 through which fuel passes fromthe inlet 22. The plug is movable axially in the upper bore section 24to selectively vary the gap or spacing G between the inner axial endface of the plug 26 and the upper end of the valve assembly to adjustthe valve lift. In the present instance the holder is provided with aradial port 27 which communicates with the spring chamber C and servesas a leak-0d bypass for fuel leaking into the spring chamber. Theleak-off bypass may be connected back to the main fuel supply if desiredand in order to seal the entire assembly there is provided an O-ring 29surrounding the holder above the leak-off bypass.

The nozzle 12 comprises a generally cylindrical body portion 30 and anelongated shank 32 of reduced cross section depending from the bodyportion. The body portion 30 has an axial bore 34 therein for the valveand a lower bore section 36 of slightly enlarged cross section to definea fuel chamber F. In the present instance a nozzle spray tip 40 ismounted in the lower terminal end of the nozzle which may be pressfitted into the enlarged open.- ing in the free end of the nozzle shank,sealed with epoxy resin and spun over for mechanical fastening. Thespray tip insert 40 has a conical seat 42 against which the valve seatsand a plurality of spray orifices 44 in the outer terminal end of thenose section 46 of the tip through which fuel is delivered to the enginecylinder.

The valve assembly comprises a streamlined head portion 50 having aconical tip 51., a tail section 52 merging with the head portion in areduced neck section 54 and an elongated tubular stem 56 mounted in asocket-like opening 58 in the tail section. The stem 56 has an axiallyextending central fuel channel 62 which at its lower end communicateswith a pair of diametrically Opposed outwardly diverging outlet holes 66in the neck of the valve. The stem 56 is secured at its inner end in thesocket 58 by means of an epoxy resin type agent and in the seatedposition of the valve, the opposite outer axial end face 0f the stem 56is spaced from the lower terminal end of the threaded member 26 toprovide a gap G determining the valve lift. In the present instance, thehead portion 50 has a double conical tapered tip which engages the valveseat in the closed position of the valve and the sidewall of the insertis also tapered to provide an inwardly converging forward section to thefuel chamber conforming generally to the tip.

The valve member is normally biased to the closed position by means of acompression spring 72 in the spring chamber C which abuts the lower endof the chamher at one end and seats on the flange 74 of a collarabutting the tail section of the valve.

In the normal operation of the fuel injection nozzle.

assembly of the present invention, the spring force of the compressionspring 72 and the pressure of the fuel acting on the axial end face ofthe stem 56 normally maintain the valve member in a closed positionwhere the conical tip 51 engages the valve seat 42. Now when the fuelpressure builds up to a predetermined amount, the valve memer is raisedupwardly against the bias of the compression spring 72 due to the areadifferential between the valve seat diameter D and the stem diameter DIn the present instance, the particular arrangement of the assemblypermits the opening and closing of the valve to be controlled veryaccurately. For example, valve opening pressure P is equal to 4F, Wvalve closing pressure P is equal to 4F 1 3 and compression spring forceF is equal to i era es-wan Now assuming a valve opening pressure of3,000 p.s.i., a valve diameter D of 0.236, a seat diameter D of 0.118and a stem diameter D of 0.0986", the spring force F is 75.6 lbs., andthe closing pressure P required is 2090 p.s.i. This contrasts withconventional assemblies where the spring load required would be aboutp.s.i. By the present arrangement, the fuel pressure acting on the areaD of the stem reduces the spring load required over conventional ductednozzles. Further by the present arrangement, by varying the diameter Dof the stem, different spring loading and pressure differences may beobtained between the opening and closing pressures.

There is illustrated in FIGS. 3, 4 and 5, another embodiment of fuelinjection nozzle in accordance with the present invention. This assemblyis generally similar in overall configuration and construction to theembodiment illustrated above and includes a nozzle holder 100, a fuelinjection nozzle 112 mounted at the lower end of the holder by means ofa cap nut 114 and a valve assembly 115 mounted in the nozzle.

The nozzle holder 100 has a fuel inlet 122 at its upper axial end and anaxially extending upper bore section 124 terminating in an enlargedlower section 125 defining a spring chamber C. A threaded plug 126 ismounted in the upper bore section 124 and has a central passage 128through which fuel passes from the inlet 122.

In the present instance the nozzle 112 is an integral assemblycomprising a generally cylindrical body portion 130 and an elongatedshank 132 of slightly reduced cross section, the body and shank havingaxial bore sections 134 and 136 respectively, the bore section 136 beingof slightly enlarged cross section and defining a fuel chamber F. Thelower end of the fuel chamber is provided with adjacent conical wallsections 137 and 139, the lower conical wall section 139 defining avalve seat and merging with a discharge opening 141 in the lower axialend of the nozzle shank.

The valve member 115 comprises a streamlined head portion 150 having atail section 152 merging with the head portion in a reduced neck section154 and an elongated hollow tubular stem 156 mounted in a socket-likeopening 158 in the tail section, the stem 156 having an axiallyextending central fuel channel 162 communicating at its lower end with apair of diametrically opposed cutwardly diverging outlet holes 166 inthe neck of the valve. The outer axial end face of the stem 156 in theseated section of the valve is spaced from the lower terminal end of theplug 126 to provide a gap G determining the valve lift. The valve isnormally biased to the closed position by means of a compression spring173 in the spring chamber C which abuts the lower end of the chamber atone end and seats on the flange 175 of a collar abutting the tailsection of the valve.

In the present instance the assembly is a poppet type assembly and tothis end the tip of the head portion 150 has a double conical taperedtip 170 which engages the valve seat in the closed position of the valveand a pintle 172 projecting from the tip through the discharge opening141 in the nozzle shank. As best illustrated in FIGS. 4 and 5, thepintle 172 has a profiled sidewall 174 consisting of an upper frustoconical wall section 176, a lower frusto conical wall section 178, whichmerges with the upper section in a rounded or gently curved neck 180 ofnarrow width. The upper wall section in the present instance is inclinedat a greater angle relative to a plane through the neck 130perpendicular to the axis of the valve. By this construction when thevalve lifts off of its seat as shown in FIG. 5 and the high pressurefuel follows the matching contours of the conical tip and seat of thevalve and nozzle shank respectively, the fuel discharges in a wideconical spray. Further by virtue of the short distance between the seat139 and the straight sided portion of the discharge opening 141, theflow of fuel is directed inwardly toward the profile portion of thepintle and then reversed as shown to issue a wide spray up to 180.

Further, in the operation of the valve due to the particularconfiguration of the fuel ducts and passageways and the streamlinedconfiguration of the valve head, flow through the fuel injection nozzleassembly may be de scribed as laminar thereby minimizing erosion andcavitation.

Moreover, by elimination of the annulus and sump, areas that tend totrap dirt and foreign particles which are dilficult to clean areeliminated. By the present arrangement, fuel injection characteristicsmay be controlled more accurately by minimizing parasitic or dead fuelvolume. Also by the particular spring mounting between the extreme endsof the valve member, deleterious side thrust due to the spring areminimized and accordingly, the valve has less tendency to stick or hangup. Lastly, the assembly of the present invention is extremelyeconomical to manufacture and with this design reduction of the nozzlediameter and miniaturization are possible.

There is illustrated in FIG. 6 still another embodiment of fuelinjection nozzle in accordance with the present invention. This assemblyis generally similar in overall construction to the previous embodimentand includes a nozzle holder 200, a fuel injection nozzle 212 positionedat the lower end of the holder by means of a cap nut 214 and a valveassembly 215 mounted interiorly of the nozzle and adapted for axialmovement therein between an open position and a closed position.

The holder 2% is an elongated generally cylindrical member having a fuelinlet 222 at its outer axial end and an axially extending upper boresection 224 which is enlarged adjacent the lower end of the holder as at225 to define a spring chamber C".

An externally threaded plug 226 is mounted in the upper bore section 224of the holder, the plug 226 having an axially extending central passage228 through which fuel passes from the inlet 222. The plug is movableaxially in the upper bore section 224 to selectively vary the gap orspacing G between the inner axial end face of the plug 226 and the upperend of the valve assembly to adjust the valve lift. In the presentinstance the holder is provided with a radial port 227 whichcommunicates with the spring chamber C and serves as a leakotf bypassfor fuel leaking into the spring chamber. The leakoff bypass may beconnected back to the main fuel supply if desired.

The nozzle 212 comprises a generally cylindrical body portion 230 and anelongated shank 232 of reduced cross section depending from the bodyportion. The body portion 230 has an axial bore 234 therein for thevalve and a lower bore section 236 of slightly enlarged cross section todefine a fuel chamber F". The lower terminal end of the nozzle bodyportion 230 has a conical seat 252 against which the valve seats and aplurality of spray orifices 243 in the tip of the nozzle shank 237through which fuel is delivered to an engine cylinder.

The valve assembly comprises a streamlined head portion 250 having aconical tip 251, and a tail section 252 merging with the conical tip ina reduced neck section 254. The tail section has a central axial bore253 which at its lower end merges with a pair of diametrically opposed,outwardly diverging outlet holes 266 in the neck of the valve. Asillustrated, the head portion 250 has a double conical tapered tip whichengages the valve seat in the closed position of the valve and theinterior sidewall of the valve body adjacent the tip is also tapered toprovide an inwardly converging forward section to the fuel chamber F"conforming generally to the tip.

In the present instance, the valve assembly includes an elongatedtubular stern assembly 256 comprising an upper section 256:: and a lowersection 256b, the upper stem section 256a being mounted in the centralpassageway in the holder having its upper end spaced from the plug 226to provide a gap or spacing G determining the valve lift. The stemsections as illustrated are elongated hollow tubular members havingaxial bores 255a and 2551) which communicate with the central opening inthe plug 226 and the bore in the tail section to permit flow of fuelfrom i the source to the fuel chamber F. As in the previously describedembodiments, the plug 226 is adjustable axially so that the valve liftmay be selectively varied. The lower stern section 25612 has taperedconical terminal ends 257 and 259 which nest in conical seats 261 in theupper stern section 256a and a conical seat 263 in the axial end face ofthe tail section of the valve. The coil spring 272 in the spring chamberC" at one end engages shims 267 mounted in the upper end of the springchamber and at its opposite end engages a radial flange 269 on the lowerend of the sleeve 271, the sleeve 271 having an inwardly directed flange273 overlying the enlarged lower end 275 of the upper stem section 2560.

In the normal operation of the fuel injection nozzle assembly describedabove, the spring forces of the compression spring 272 and the pressureof the fuel acting on the axial end face of the upper stem assembly 2560normally maintain the valve member in a closed position wherein theconical tip 251 engages the valve seat 252. Now when the fuel pressurebuilds up to a predetermined amount, the valve member is raised upwardlyagainst the bias of the compression spring due to the area ofdifferential of the valve seat diameter D; and the stem diameter D Inthe present instance the two-piece stern assembly 256a and 2561:provides flexibility and eliminates excessive side thrusts on the valve.Further, in order to eliminate leakage of high pressure fuel at thejunclure of the lower stem section 25Gb with the upper stem section andvalve, the mating angular surfaces have a different angle of taper sothat the parts seat on the ouside diameter. Preferably the includedangle A on the ends of the lower stem section 25611 is greater than thecounter-sink angle on the seats in the upper stern section and valve.For ex- 7 ample, if the included angle A is 90, then the countersinkangles B for the seat in the tail section and the seat on the lower endof the stem aszembly are between 80-S5.

While particular embodiments of the present invention have beenillustrated and described herein, it is not intended to limit theinvention and changes and modifications may be made therein within thescope of the following claims.

I claim:

1. A fuel injection nozzle assembly comprising an elongated holder, anozzle mounted at one axial end of the holder, means defining a firstaxial bore in the nozzle defining a fuel chamber, valve member meansmounted for axial movement in said bore between open and closedpositions, a fuel inlet in the axial end of said holder opposite saidone axial end, means defining a second axial bore in said holdercommunicating with said inlet, said valve member including an elongatedstem engaging in said second axial bore, said stem having a central fuelpassage communicating at its inner end with a pair of angled fuelpassageways in said valve member which in turn communicates with saidfuel chamber.

2. A fuel injection nozzle assembly as claimed in claim 1 including aplug mounted in said second axial bore having its inner end normallyspaced from an axial end of said stem providing a gap determining valvelift.

3. A fuel injection nozzle as claimed in claim 2 wherein said plug ismovable axially in said bore whereby the gap may be varied selectivelyto vary valve lift.

4. A fuel injection nozzle assembly as claimed in claim 1 including anenlarged lower bore section in said one end of the holder defining aspring chamber and including a spring in said chamber circumscribingsaid stem.

5. A fuel injection nozzle assembly as claimed in claim 1, wherein saidvalve member has a streamlined head portion including a conical tip, atail section merging with the head portion in a reduced neck section.

6. A fuel injection nozzle assembly as claimed in claim 1 including atip insert mounted in the axial bore in the free end of said nozzle.

7. In a fuel injection nozzle assembly including a holder having a fuelinlet, a nozzle having a first axial bore defining a fuel chamber, adischarge opening in one axial end of the nozzle and a valve seatadjacent the discharge opening, valve member means mounted in said fuelchamber having a streamlined head portion including a conical taperedtip, a pintle projecting from the tip, said pintle consisting of anupper frusto-conical wall section, a lower frusto conical wall sectionwhich merges with the upper wall section in a rounded neck of reducedcross section, means defining a second axial bore in said holdercommunicating with said inlet, said valve member including an elongatedstem engaging in said second axial bore, said stem having a central fuelpassage communicating at one end with said inlet and at said oppositeend with said fuel passage in said valve member which in turncommunicates with said fuel chamber, said valve member adapted for axialmovement in said first axial bore between a closed position wherein thetip engages the nozzle seat and an open position wherein the tip isspaced from the seat whereby fuel discharges in a wide conical spray.

8. A fuel injection nozzle assembly comprising an elongated holder, anozzle mounted at one axial end of the holder, means defining a firstaxial bore in the nozzle defining a fuel chamber, valve member meansmounted for axial movement in said bore between open and closedpositions, a fuel inlet in the axial end of said holder opposite saidone axial end, means defining a second axial bore in said holdercommunicating with said inlet, said valve member including an elongatedstem engaging in said second axial bore, said stem having a central fuelpassage communicating at one end with said inlet and at its opposite endwith a fuel passage in said valve memher which in turn communicates withsaid fuel chamber.

9. A fuel injection nozzle assembly as claimed in claim 8 wherein saidstem comprises an upper stem section engaging in said second axial boreand a lower stem section at one end engaging the upper stem section andat its opposite end engaging the upper axial end face of the valvemember.

10. A fuel injection nozzle assembly as claimed in claim 9 wherein saidlower stem section has tapered conical terminal ends which engage inconical seats in the upper stem section and valve member respectively.

11. A fuel injection nozzle assembly as claimed in claim 10 wherein theangle of taper at the terminal ends of the lower stem section is greaterthan the included angle of said conical seats.

References Cited UNITED STATES PATENTS 3,224,684 12/1965 Roosa 2395333,244,377 4/1966 Roosa 239-533 3,255,974 6/1966 Roosa 239-533 FOREIGNPATENTS 1,121,065 4/ 1956 France.

592,519 2/ 1934 Germany.

617,795 2/1949 Great Britain.

746,785 3/1956 Great Britain.

EVERETT W. KIRBY, Primary Examiner.

